1. Field of the Invention
The invention relates generally to a liquid seal and to a method for operating a liquid seal which is located upstream of a flare stack or of a waste gas combustion system, wherein a stream of gas is introduced into the liquid seal by a gas delivery tube having an outlet end submerged in a dammed-up liquid contained in the seal.
2. Description of Prior Art
Liquid seals are conventionally installed upstream of flare stacks or waste gas combustion installations for safety reasons. A liquid seal is intended to serve a dual purpose. On one hand, the seal provides protection against a flashback, and on the other hand the seal functions as a pressure lock for the gas stream. Prior art liquid seals do not perform these dual functions satisfactorily because fluctuations occur in the level of the liquid in the liquid seal which result in gas pulsations and/or the ejection of liquid from the liquid seal. The ejection of liquid is undesirable because it causes the liquid, which is generally water, to contact the flare stack where it adversely affects combustion. The maintenance of pressure by using a liquid seal as a pressure lock is necessary to prevent oxygen from entering the system upstream of the liquid seal. Gas pulsations which occur in the liquid seals of the prior art significantly interfere with the combustion at the flare stack or in the waste gas combustion installation and threaten the operational safety of the system.